This research paper presents SIMPL (Scalable Iterative Maximization of Population-coded Latents), a novel, computationally efficient algorithm designed to refine the estimation of latent variables and tuning curves from neural population activity. Latent variables in neural data represent essential low-dimensional quantities encoding behavioral or cognitive states, which neuroscientists seek to identify to understand brain computations better. Background and Motivation Traditional approaches commonly assume the observed behavioral variable as the latent neural code. However, this assumption can lead to inaccuracies because neural activity sometimes encodes internal cognitive states differing subtly from observable behavior (e.g., anticipation, mental simulation). Existing latent variable models face challenges such as high computational cost, poor scalability to large datasets, limited expressiveness of tuning models, or difficulties interpreting complex neural network-based functio...
The Pedunculopontine Nucleus (PPN) is a group of neurons located in the brainstem, specifically in the pontine region. Here is an overview of the Pedunculopontine Nucleus: 1. Anatomy : o The PPN is situated in the rostral part of the brainstem, near the junction of the pons and midbrain. It is part of the reticular formation, a network of neurons involved in various physiological functions. o The PPN receives inputs from multiple brain regions, including the basal ganglia, thalamus, and cortex, and sends outputs to structures involved in motor control, arousal, and gait. 2. Function : o Motor Control: The PPN is implicated in the regulation of motor functions, particularly in the control of posture, locomotion, and movement initiation. It is involved in coordinating rhythmic movements and adjusting gait patterns. o Arousal and Attention: The PPN is also associated with arousal, wakefulness, and attention. It plays a role in regulat...